The U.S. Department of Energy (DoE) this week released a final rule for some types of walk-in coolers and freezers, according to the Appliance Standards Awareness Project (ASAP).

It is a long process. ASAP says that a final ruling for walk-in coolers and freezers were established in 2014. At that point, however, the Air-Conditioning, Heating, and Refrigeration Institute (AHRI) and others filed a lawsuit. A resulting settlement sent six of the 19 classes of the equipment back to the DoE for a new rulemaking using a negotiated process.

The results, which are the subject of the rule released this week, are expected to cut energy use by about 90 billion kilowatt-hours (kWh) over 30 years and save businesses as much as $4 billion. The final rule is expected to be completed this year and to take effect in three years.

Increasing the efficiency of commercial refrigeration equipment is an area of acute interest for energy managers, particularly in the grocery and convenience store sector.